R Programming: Extract Specific Columns from a Data Frame

R Programming: Data frame Exercise-5 with Solution

Write a R program to extract specific column from a data frame using column name.

Sample Solution :

R Programming Code :

 # Create a data frame named 'exam_data' with columns 'name', 'score', 'attempts', and 'qualify'
exam_data = data.frame(
  # Column 'name' with character values
  name = c('Anastasia', 'Dima', 'Katherine', 'James', 'Emily', 'Michael', 'Matthew', 'Laura', 'Kevin', 'Jonas'),
  # Column 'score' with numeric values
  score = c(12.5, 9, 16.5, 12, 9, 20, 14.5, 13.5, 8, 19),
  # Column 'attempts' with numeric values
  attempts = c(1, 3, 2, 3, 2, 3, 1, 1, 2, 1),
  # Column 'qualify' with character values
  qualify = c('yes', 'no', 'yes', 'no', 'no', 'yes', 'yes', 'no', 'no', 'yes')
)

# Print the message "Original dataframe:"
print("Original dataframe:")

# Print the content of the 'exam_data' data frame
print(exam_data)

# Print the message "Extract Specific columns:"
print("Extract Specific columns:")

# Create a new data frame 'result' with only the 'name' and 'score' columns from 'exam_data'
result <- data.frame(exam_data$name, exam_data$score)

# Print the content of the 'result' data frame
print(result)

Output:

[1] "Original dataframe:"
        name score attempts qualify
1  Anastasia  12.5        1     yes
2       Dima   9.0        3      no
3  Katherine  16.5        2     yes
4      James  12.0        3      no
5      Emily   9.0        2      no
6    Michael  20.0        3     yes
7    Matthew  14.5        1     yes
8      Laura  13.5        1      no
9      Kevin   8.0        2      no
10     Jonas  19.0        1     yes
[1] "Extract Specific columns:"
   exam_data.name exam_data.score
1       Anastasia            12.5
2            Dima             9.0
3       Katherine            16.5
4           James            12.0
5           Emily             9.0
6         Michael            20.0
7         Matthew            14.5
8           Laura            13.5
9           Kevin             8.0
10          Jonas            19.0                         

Explanation:

• Create a Data Frame:
• exam_data = data.frame(...)
• Creates a data frame named exam_data with four columns: name, score, attempts, and qualify.
• name contains character values representing names.
• score contains numeric values representing scores.
• attempts contains numeric values representing the number of attempts.
• qualify contains character values indicating whether the person qualifies.
• Print the Original Data Frame:
• print("Original dataframe:")
• Prints the message "Original dataframe:" to indicate the start of the data frame output.
• print(exam_data)
• Displays the contents of the exam_data data frame.
• Extract Specific Columns:
• print("Extract Specific columns:")
• Prints the message "Extract Specific columns:" to indicate the start of the extraction process.
• result <- data.frame(exam_data$name, exam_data$score)
• Creates a new data frame result with only the name and score columns from the exam_data data frame.
• print(result)
• Displays the contents of the result data frame, showing only the name and score columns.

R Programming Code Editor:





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